Britney Spears commanded the world's attention when she walked through the halls in a school girl skirt and pigtails 20 years ago today ... yes, we're old ... and now she's reminiscing on the day her iconic hit dropped.

Spears shared a short behind the scenes clip from filming the music video back in 1998, thanking her fans who've been with her since day 1.

"It’s hard to put into words what today means to me," adding "20 years ago, the world heard my music for the very first time! So much has happened since then… but what I really want to say is thank you to my amazing fans who have been there for me since day 1."

The singer gushed, "Your support over the years has meant the absolute world to me!! Love you all! ❤️❤️❤️."

"Baby One More Time" was quite the hit for Spears hitting No. 1 on the Billboard 200 charts that same year, and went on to sell more than 25 million copies worldwide.

Following that high, Spears picked up four awards at the 1999 Billboard Music Awards, including for female artist of the year and best new artist.

Two decades later, a Grammy and two Vegas residencies underneath her belt, we have to say Britney only gets better with time!

BTW, some other things with a 20th Anniversary this year to make you feel nice and old: Netflix, iMacs and Viagra.